Re: [PATCH v1 5/5] KVM: s390: vsie: gmap_table_walk() simplifications

David Hildenbrand
2020-04-03T13:09:31Z

On 03.04.20 15:03, Janosch Frank wrote:
> On 4/2/20 8:48 PM, David Hildenbrand wrote:
>> Let's use asce_type where applicable. Also, simplify our sanity check for
>> valid table levels and convert it into a WARN_ON_ONCE(). Check if we even
>> have a valid gmap shadow as the very first step.
>>
>> Signed-off-by: David Hildenbrand <david@redhat.com>
>> ---
>> arch/s390/mm/gmap.c | 7 ++++---
>> 1 file changed, 4 insertions(+), 3 deletions(-)
>>
>> diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
>> index fd32ab566f57..3c801dae7988 100644
>> --- a/arch/s390/mm/gmap.c
>> +++ b/arch/s390/mm/gmap.c
>> @@ -790,17 +790,18 @@ static inline unsigned long *gmap_table_walk(struct gmap *gmap,
>> const int asce_type = gmap->asce & _ASCE_TYPE_MASK;
>> unsigned long *table;
>>
>> - if ((gmap->asce & _ASCE_TYPE_MASK) + 4 < (level * 4))
>> - return NULL;
>> if (gmap_is_shadow(gmap) && gmap->removed)
>> return NULL;
>>
>> + if (WARN_ON_ONCE(level > (asce_type >> 2) + 1))
>> + return NULL;
>> +
>> if (WARN_ON_ONCE(asce_type != _ASCE_TYPE_REGION1) &&
>> gaddr & (-1UL << (31 + (asce_type >> 2) * 11)))
>> return NULL;
>>
>> table = gmap->table;
>
> We could also initialize this variable at the top, no?

very right, add that.

--
Thanks,

David / dhildenb